[Illustration: FIG. 72.--Brachiopod, showing supporting loop.] [Illustration: FIG. 73.--The leech of commerce: _a_, anterior sucker; _b_, posterior sucker; _d_, stomach; _s_, glands of the skin.] The best known of all worms, perhaps, because all boys are fond of fishing, is the angleworm or earthworm (Fig. 74), which can be found where the earth is rich and moist. This worm is really a beautiful object, being highly iridescent, flashing a thousand hues in the sunlight to which it has a decided objection, as the heat soon dries it up. The ringed or segmented arrangement is easily observed as it moves along. By this marvelous arrangement a worm can either stretch itself out to an inordinate length, or telescope itself until it can hardly be recognized as a worm. There are several interesting features about earthworms which ordinarily escape the notice of even the angler. One is its feet, which differ from those of any other animal. They are very minute, and are bristles, each segment or ring being supplied with four. Another peculiarity of the earthworm is that instead of hunting out food in the earth it swallows the earth as it meets it, allowing the animal matter to be absorbed within. It then casts up the earth, which are the little mounds of mold found in the grass or turf every morning. This habit has made the worm a valuable aid to the farmer in preparing the soil, filling it with tunnels and constantly bringing new earth to the surface and turning it over. The amount of earth moved in this way was made a special study by Charles Darwin. In the year 1842 he spread a field with broken chalk, and after twenty-nine years examined it and found that the chalk in that time had been buried seven inches by the worms. [Illustration: FIG. 74.--Earthworm: _c_, egg; _d_, young escaping from egg.]